Town of Beloit police said the mother's half-sister, Kristen Smith, was taken into custody in Iowa on Thursday on an unrelated warrant. She had been at the family home in Beloit and said she was on her way back to her home in Colorado when Kayden disappeared.

Police said they called Smith on her cellphone, and she agreed to pull over in Iowa. Police said she had baby clothing in her car, but there was no sign of the newborn.

Authorities are currently holding Smith on an unrelated warrant but now call her a person of interest in this case.

Kopp said Kayden was found "in the general area" where Smith pulled over to await police on Thursday.

WE HAVE BEEN WORKING NONSTOP HOPING FOR THIS DAY. AT APPROXIMATELY 10:15 THIS MORNING, MY CORE IKE FOUND CADEN IN A TOTE BAG IN A GAS STATION NEAR INTERSTATE 80. DESPITE FRIGID TEMPERATURES, HE WAS FOUND ALIVE AND APPEARS TO BE DOING VERY WELL. IN THE WORDS OF OFFICIALS, HE IS IN EXCELLENT HEALTH. HIS FAMILY HAS BEEN NOTIFIED OF THIS FANTASTIC NEWS. I WEAR EFFORTS NOW CENTER ON REUNITING THE FAMILY WITH CADEN. OUR INVESTIGATION WILL CONTINUE UNTIL ALL POTENTIAL LEADS HAVE BEEN EXHAUSTED. THIS OUTSTANDING INVESTIGATION WAS A MODEL OF COLLABORATION AND COOPERATION BETWEEN THE TOWN OF BELOIT POLICE DEPARTMENT, THE ROCK COUNTY SHERIFF'S OFFICE, THE WISCONSIN DEPARTMENT OF JUSTICE DIVISION OF CRIMINAL INVESTIGATION, THE FEDERAL BUREAU OF INVESTIGATION, THE ILLINOIS STATE POLICE, THE IOWA STATE PATROL, THE WEST BRANCH IOWA POLICE DEPARTMENT AND OTHER PUBLIC AND PRIVATE PARTNERS TOO NUMEROUS TO MENTION. SPECIAL THANKS TO THE MEDIA FOR ASSISTING US IN GETTING